Hi, welcome to lecture two of section five. We'll take a look at the muscles of the back and at the medial side of scapula. There are a lot of muscles that extend and rotate the back, but I will explain about the various systems we can tell apart. And with that in mind, you will be able to keep track. The first group is erector spinae group. This group is made out of muscles with long vertical fibers.

Closest to the midline, we can see spinners. Its fibers start from the spine is processes of the upper lumbar and lower thoracic vertebrae, as well as the low cervical and high thoracic vertebrae and insert at the spine as processes of the upper thoracic and cervical vertebrae, but not c one. A little further aside from the midline, we can see longest image The lower part is called longest swimmers through races. It's fibers share a common tendon that originates from sacrum and the iliac crest. Other origins are the lumbar vertebrae. The fibers arise and inserted all transverse processes of the thoracic vertebrae and the lower nine ribs.

The upper parts are called longest summer surfaces, and longest humerus cavities. Nagashima services and capital both arise from the transfers processes of thoracic vertebrae services arises from T one to T six, and inserts at C two to C five. Now it seems capitis starts at C four, two t three. And from there the fibers go straight up to the mastoid process of cranium. Number three of the erector spinae group is called bleah cost analysis because it starts at the ilium and ends at the cost at the ribs. The common tendon of the lumber part starts at the iliac crest and sacrum.

The fibers go up and attach at the lumbar vertebrae here and at the sixth level ribs. The thoracic part starts from the six lower ribs and inserts at the upper ribs. The cervical part starts at the six upper ribs and inserts at the transverse processes of the lower cervical vertebrae. They all extend the spine, but if they work unilaterally, they side flex the spine to the same side. Then we get to talk about the transfer so spin on this group. Well, the erector spinae group has vertical fibers This group's fibers are all oblique, or diagonal.

The deepest ones are rotators. They span one to two first Bray. The origins are the transverse processes and the insertions, the spinal processes. But if you die, spend two to four vertebrae and have the same origins and insertions. The last muscle in this group is semi spin Alice cavities. This muscle starts at the transfers processes of T five to c four, and inserts at oxy put the back of cranium it extends the cervical spine and the head as well.

The full transversal spinners group extends the spine and when working unilaterally, the muscles in this group rotate the spine to the opposite side. The any meenie miney muscles that are even smaller than rotators and Mills If you die deep down in the back are left out of this course. We do need to look at five other muscles however quadratus lumborum, both rhomboids lavato scapulae serratos anterior and trapezius. quadratus lumborum starts at the posterior iliac crest, and inserts at the last rib and the transverse processes of lumbar vertebrae 123 and four. It can tilt the pelvis inside flex the spine, but also helps in extending the lower back. way up the spine we can see the fatter scapulae.

The Vater is many times classified as a neck muscle, but because its location is so in line with the rhomboids hereafter, I decided to discuss your photo here. The origins are the transfers processes of C one to c four. And the insertion is at the medial border of scapula above the scapular spine. Right below the fighter we can see the rhomboids They come in a pair rhomboid minor and rhomboid major the origins are here at the medial border of scapula and they insert that the spine is processes c 71 for rhomboid minor and T two t five for rhomboid major. Both muscles main function is to adduct or retract scapula. The opposite movement of retracting scapula is protracting.

This is done by serratos anterior, its origin is at the inner side of the medial border of scapula and the insertions are the surfaces of the upper eight or nine ribs. Besides protracting this muscle is very important in keeping the scapular stick to the last thick wall, otherwise it will stand out like a wing. The last muscle in this lecture will be trapezius muscle with three sub muscles called the descending transfers and ascending trapezius. Because of the direction the fibers go together they look like one our giant muscle. The origin of trapezius starts at the occiput and then downwards to t 12. The descending trapezius uses the spinal processes c one to C seven.

The transfers trapezius starts at the apple neuroses from T one to T four, and the ascending part arises from spinal processes t five to t 12. Let's look at the insertions of all three parts of trapezius now. The descending part inserts at the lateral third of clavicular. The transfers part at the ends Have a chromium and most of spinner scapulae and the ascending part inserts at the basis of spinal scapula. The descending trapezius lifts the shoulders and side flexes the neck. The transfers part retract scapula together with rhomboids and the sending part immediately rotates scapula and takes a stabilizing role in the scapula movements.

As you might have noticed, the muscles of the back are active in some movements of the neck and head as well. Last lecture of anatomy basic scores, we'll discuss the muscles of the neck. Thank you for watching this lecture, and I hope to see you in the last and final lecture of anatomy basics.